Angular Velocity Sensor Disconnection Detection via C/V Conversion
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Solution Overview
Problem
Existing angular velocity sensors face challenges in accurately detecting disconnection of the driving signal transmission line, particularly when the sensor is in an ideal condition without oblique vibration, as the servo control is not necessary, leading to undetectable disconnections.
Innovation Solution
An angular velocity sensor configuration that includes a vibration correcting part with movable and driving electrodes, a C/V converter circuit, and a determination part to detect disconnection by converting capacitance into voltage, allowing for disconnection detection even without oblique vibration, using a second-axis vibration restricting part to control electrostatic forces and a C/V converter circuit to determine voltage changes indicative of disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is in an ideal condition without oblique vibration, then the servo control is not necessary and the system operates simply, but the disconnection of the driving signal transmission line becomes undetectable
Solution Approach 1:
The patent applies preliminary action by performing disconnection detection before normal operation begins. The detection unit checks the connecting portion between sensor unit and detection unit prior to activating the vibrator and servo control. This allows disconnection to be detected in advance, even in ideal conditions where oblique vibration would not normally occur, without requiring continuous complex servo control for detection purposes.
Solution Approach 2:
The patent implements self-service by having the detection unit utilize existing structural components (vibrator, connecting portion) for both normal operation and disconnection detection. The detection unit self-diagnoses the connection status using the same physical pathways through which driving signals pass, eliminating the need for separate dedicated detection hardware or continuous servo control activation.
2Measurement precision
If the connecting portion has disconnection, then the angular velocity cannot be accurately detected and malfunction occurs, but existing disconnection detection methods fail when servo control is not active
Solution Approach 1:
The patent performs disconnection detection before normal angular velocity measurement begins. The detection unit checks the connecting portion integrity in advance, ensuring that the measurement pathway is intact before attempting accurate angular velocity detection. This preliminary check prevents measurement errors that would result from undetected disconnections.
Solution Approach 2:
The patent uses the connecting portion itself as an intermediary element that serves dual purposes: transmitting driving signals during normal operation and serving as the detection target for disconnection detection. By monitoring the electrical characteristics of this intermediary pathway, the system can detect disconnections without requiring separate sensing mechanisms.
3Manufacturing precision
If the vibrator is ideally machined, then the vibrator merely vibrates in the X-axis direction without oblique vibration, but the driving signal for servo control does not pass through the connecting portion making disconnection undetectable
Solution Approach 1:
The patent performs connection integrity verification before normal operation begins, regardless of vibrator machining quality. The detection unit checks the connecting portion in advance, ensuring that even ideally machined vibrators have intact connection pathways. This preliminary verification is independent of the vibrator's vibration characteristics, ensuring reliable connection status detection for all manufacturing quality levels.
Solution Approach 2:
The system uses self-service by having the detection unit verify connection integrity using the same electrical pathways that will carry driving signals during normal operation. This self-verification mechanism works regardless of vibrator machining precision, as it directly tests the connecting portion rather than inferring connection status from vibration behavior.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate detection of disconnection in the driving signal transmission line, ensuring reliable operation even when the sensor is in an ideal state without oblique vibration, thereby preventing malfunctions due to undetected disconnections.
Implementation Method 1
a driving electrode opposed to the movable electrode and generating an electrostatic force between the movable electrode and the driving electrode to move the movable part in the second direction
Implementation Method 2
a C/V converter circuit configured to receive a capacitance between the movable electrode and the driving electrode through the driving signal transmission line in a state where supply of the driving signal is stopped, and convert the capacitance into a voltage
Implementation Method 3
When an angular velocity is applied around a Z-axis that is perpendicular to the X-axis and the Y-axis, the vibrator vibrates in the Y-axis direction due to Coriolis force caused by the angular velocity
Data Source
AI summary
An angular velocity sensor includes a sensor unit, a detection unit and a connecting part electrically connecting the sensor unit and the detection unit. The detection unit drives the sensor unit and detects an angular velocity acting on the sensor unit. The detection unit supplies a carrier signal to a movable electrode of a capacitor of the sensor unit and supplies a driving signal to a fixed electrode of the capacitor via the connecting part for performing a servo control. A C/V converter circuit of the detection unit receives capacitance generated at the capacitor through a driving signal transmission line of the connecting part in a state where supply of the driving signal is stopped, and converts the capacitance into a voltage. A determination part of the detection unit determines whether the driving signal transmission line has disconnection or not based on the voltage outputted from the C/V converter circuit.